JP4899060B2 - Heat treatment system for waste containing asbestos - Google Patents

Description

  The present invention relates to a heat treatment system that heats asbestos-containing waste with superheated steam and renders it harmless.

  Asbestos (asbestos) is a natural ore in which serpentine and amphibole are deformed into fibers, and is classified into serpentine-based chrysotile, amphibole-based crocidolite, amosite, and the like. Asbestos is excellent in lightness, durability, heat resistance, chemical resistance, electrical insulation, and is inexpensive, so far it has been widely used in various applications such as construction materials, electrical products, automobiles, and household products. It was.

  In recent years, asbestos has a problem of causing diseases such as lung cancer and mesothelioma because its fibers are easily scattered in the air. Therefore, at present, shipment of products containing asbestos exceeding 0.1% of the total weight is prohibited in principle. In addition, in the disposal of used asbestos-containing waste, asbestos-containing waste exceeds 0.1% of the total weight in the law enforcement regulations on waste disposal and cleaning. It is required to make asbestos non-asbestos until it is 0.1% or less of the total weight.

  A melt processing technique is known as a technique for detoxifying asbestos. The melting treatment technique is a technique for heating to a melting point of asbestos, that is, a temperature of 1500 ° C. or more and detoxifying the asbestos by melting. The processing apparatus employed in this technique includes a melting furnace for containing the charged asbestos and heating the asbestos to 1500 ° C. or more to melt it.

  This device requires a great amount of energy during operation, and must be made of a material that can withstand a temperature of 1500 ° C. or higher, resulting in high equipment costs and operation costs. The melt discharged from this apparatus is not reused, and most of it is currently landfilled at the final disposal site. As a result, processing costs for landfilling the melt are also incurred.

  Therefore, a heat treatment method has been proposed as a technique for detoxifying asbestos-containing waste at low equipment costs and low operation costs (see Non-Patent Document 1). In this method, the structure of asbestos is changed by heating to render it harmless. Since this heat treatment can be performed at a lower temperature than the melting treatment, asbestos detoxification can be realized at a low equipment cost and a low operation cost.

Note that Non-Patent Document 1 requires that “heating at 1000 ° C. for 3 hours” is necessary as a heating condition evaluated as not containing asbestos by phase contrast microscopy in accordance with JIS A 1481, 800 ° C. At 900 and 900 ° C., it is described that detoxification according to the above criteria cannot be performed. This is because the thermal conductivity of asbestos is low at temperatures of 800 ° C. and 900 ° C. lower than 1000 ° C., so the temperature does not reach the inside of the asbestos and the temperature distribution is not uniform. Without heating, it indicates that there is unreacted chrysotile.
Shinobu Hashimoto, Atsushi Okuda, Satoshi Uebayashi, Yuu Honda, Hideo Awaji, Koichiro Fukuda, "Evaluation of Heated Chrysotile by Phase-Contrast Microscopy", Journal of the Ceramic Society of Japan, 114 [8] 716-718, 2006 August 1

  In the above heat treatment method, chrysotile is placed in an alumina crucible, heated in an electric furnace at 600 ° C. to 1100 ° C. for 3 hours, and after heating and holding, the electric furnace is turned off and naturally cooled to room temperature. However, this requires a time for heating from room temperature to 600 ° C. to 1100 ° C., a time for holding at that temperature, and a time for natural cooling to room temperature in the electric furnace, and the processing efficiency is extremely low. There is.

  Accordingly, it is desired to provide a heat treatment method and an asbestos-containing waste treatment apparatus with high treatment efficiency.

As a result of intensive studies, the inventors of the present invention heated the asbestos-containing waste in an overheated steam atmosphere, so that the crystal water in the asbestos was at a temperature lower than 1000 ° C. such as 800 ° C. and 900 ° C., and for about 30 minutes. It was found that the chrysotile disappeared completely by dehydration in such a short time, mainly 2CaO.SiO ₂ and CaO.

  Based on this, a plurality of plate-like asbestos-containing wastes are separated from each other by a spacer or the like so that superheated steam can circulate, and accommodated in a container having a plurality of holes in the separated state. Put it in a heater equipped with heating means, supply superheated steam from the superheated steam generator and heat it to about 900 ° C with the heating means while keeping the inside of the heater in a superheated steam atmosphere, hold it for about 30 minutes, and then take out the whole container In order to evaluate whether or not asbestos is contained, a qualitative analysis by a disperse staining method using a phase contrast micrograph and a quantitative analysis by an X-ray diffraction analysis method are performed. It has been found that there is no chrysotile, and asbestos can be detoxified at a low temperature in a short time at a time.

  This invention is made | formed by discovering the above, The said subject can be solved by providing the heat processing system of this invention.

That is, according to the present invention, a plurality of asbestos-containing wastes are stored separately from each other, and a container having a plurality of holes on the side surface and the bottom surface,
A superheated steam generator for generating superheated steam;
By providing a heating means for heating a plurality of asbestos-containing wastes, containing a container, receiving superheated steam from a superheated steam generator, and heating the plurality of asbestos-containing wastes by a heating means under a superheated steam atmosphere And a heater that dehydrates the crystal water in the asbestos and renders the asbestos harmless.

  The container can contain a plurality of asbestos-containing wastes that are spaced apart from each other with spacers interposed therebetween. As the spacer, a spacer that has become a small piece at the stage of peeling the asbestos-containing building material can be used. In addition, although this small piece also contains asbestos, the crystal water in asbestos can be dehydrated and detoxified by heating in a superheated steam atmosphere.

  The heater can accommodate a plurality of containers and heat-treat a plurality of asbestos-containing wastes accommodated in the plurality of containers at a time. Thereby, many asbestos containing waste materials can be heat-processed at once, and processing efficiency can further be improved.

  The heating means can be an electric heater attached inside or outside the heater. Moreover, it can also heat by the combustion of gas from the exterior of a heater.

  In the heater, a plurality of asbestos-containing wastes can be heated in a superheated steam atmosphere at a temperature of about 800 ° C. to 1100 ° C. for about 10 minutes to 120 minutes.

  The heat treatment system is further installed at the rear stage of the heater, accommodates the container, sprays water toward the heated plurality of waste containing asbestos, cools the plurality of waste containing asbestos, and heats A cooler that discharges superheated steam generated from a plurality of waste containing asbestos, and a plurality of heaters that are installed in the front stage of the heater, contain the container, and are contained in the container by the superheated steam discharged from the cooler. And a preheater for preheating the asbestos-containing waste. By including these, heat efficiency can be improved and heat treatment can be realized with low energy.

  In addition, a plurality of preheaters having different heating temperatures and coolers having different cooling temperatures can be included. The preheater is installed so that the heating temperature becomes higher toward the heater, and the cooling temperature is increased as the heater is moved away from the heater. The cooler can be installed so as to be low. In this case, the preheater installed immediately before the heater may not be heated to a desired temperature by a cooler installed immediately after the heater or superheated steam discharged from the heater. If you want to heat to about 800 ° C with a preheater, but the superheated steam discharged from the heater is about 900 ° C, then heating the asbestos-containing waste to about 800 ° C with superheated steam at a temperature of about 900 ° C Have difficulty. In such a case, the preheater installed immediately before the heater is provided with heating means such as an electric heater like the heater, and can be heated to a desired temperature by the heating means.

  The heater can include an inlet for receiving asbestos-containing waste and an outlet for discharging the heat-treated waste. In this case, it is provided with a transport device that is installed in the heater and transports the container from the receiving port to the discharge port, and a basket that contains a plurality of asbestos-containing wastes. And a waste input device that inputs the material into a container disposed on the transfer device via a receiving port. By transporting a plurality of asbestos-containing wastes one by one, it is possible to improve work efficiency and perform processing in a short time.

  The heat treatment system may further include a reaction device that reacts the superheated steam discharged from the heater with the volatile organic compound generated from the asbestos-containing waste to decompose the volatile organic compound. Asbestos-containing building materials may contain volatile organic compounds such as formaldehyde and cannot be released into the atmosphere because they affect the human body. For this reason, some kind of treatment is required, but by using this reaction apparatus, it can be reacted with superheated steam and decomposed into a harmless gas such as low-molecular carbon dioxide.

  By providing the heat treatment system of the present invention, more asbestos-containing waste can be rendered harmless in a short time and with low energy.

  Moreover, since it can be detoxified by heating at a low temperature for a short time, safety and reliability can be sufficiently ensured.

  Before describing the heat treatment system of the present invention, asbestos and asbestos-containing waste will be described, and the effects of heating them in a superheated steam atmosphere will be described.

  Asbestos is a naturally occurring mineral fiber of silicate hydrate, including serpentine chrysotile, amphibole crocidolite and amosite. Asbestos dehydrates crystal water by heating at high temperature. Here, the chemical formula for dehydration of asbestos crystal water is shown in Formula (1) for chrysotile, Formula (2) for amosite, and Formula (3) for crocidolite.

As shown in Formulas 1 to 3, chrysotile and amosite are dehydrated and converted into harmless forsterite (Mg ₂ SiO ₄ ), and crocidolite is dehydrated and harmless sodium silicate (Na ₂ SiO ₄ ). Change to ₃ ). Therefore, asbestos can be rendered harmless by heating at a high temperature.

  Examples of the waste containing asbestos include scatterable asbestos-containing waste having a remarkably large amount of dust generation or dust generation, and non-scatterable asbestos-containing waste having a relatively low dust generation property. Dispersible asbestos-containing waste includes asbestos spraying materials, heat insulating materials containing asbestos, heat insulating materials, fireproof coating materials, etc., and non-scattering asbestos-containing waste includes molded plates such as decorative slate for residential roofs. is there. All the asbestos-containing wastes exemplified here are plate-shaped.

  Superheated steam has a specific heat twice that of air, has a larger convective heat transfer effect than air, and has a heat transfer effect due to heat radiation and condensed water, so it is lower in temperature and shorter than heating in air. The amount of heat required in time can be given to the object to be heated.

  Actually, when 100% chrysotile asbestos is heated in a superheated steam atmosphere and then quantitative analysis is performed by X-ray diffraction analysis, it is about 30 minutes at a temperature of 700 ° C. or higher as in the case of heating in air. Upon heating, no chrysotile peak was detected. Instead, a forsterite peak was detected, indicating that forsterite was produced.

  When qualitative analysis is performed using a dispersion dyeing method using a phase contrast micrograph, fibers exhibiting a magenta-blue dispersion color are present at a heating temperature of 700 ° C. As a result of qualitative analysis using this dispersion dyeing method, asbestos is rendered harmless. It was shown that you can't. However, it was shown that when the heating temperature was 800 ° C., the fibers exhibiting a magenta-blue dispersion color disappeared completely, and asbestos could be rendered harmless.

  In addition, the qualitative analysis result by this disperse dyeing | staining method showed that even if it heated at 700 degreeC for 180 minutes, the fiber which shows a magenta-blue disperse color exists, and asbestos cannot be detoxified. On the other hand, when the temperature was set to 800 ° C., even when heating was performed for 10 minutes, the fibers exhibiting a magenta-blue dispersion color disappeared completely, indicating that asbestos could be rendered harmless.

  When qualitative analysis and quantitative analysis for evaluating the detoxification of asbestos are performed on spray materials and decorative slate for residential roofs, under superheated steam atmosphere, about 800 to 1100 ° C, about 10 to 120 minutes The chrysotile disappeared completely by heating. From this, asbestos-containing waste such as asbestos spray material and slate can be heated at a temperature of about 800 ° C to 1100 ° C in a superheated steam atmosphere, and all chrysotile can be removed in a short time of about 10 minutes to 120 minutes. Can be eliminated and detoxified.

  The amount of superheated steam required for heating. For example, when 5 g of 100% chrysotile asbestos is put in a 0.3 L container and heated to 800 ° C., the chrysotile has an atomic weight of 277.1 (kg / kmol). The heating produces about 0.65 g (about 3.2 L) of superheated steam. This 3.2 L of superheated steam is an amount that can be sufficiently filled for a capacity of 0.3 L of the container. From this, a superheated steam atmosphere can be formed from crystal water dehydrated from asbestos. However, depending on the content of asbestos in the waste, the capacity of the container, etc., it may not be able to be fully satisfied, and as the amount of superheated steam increases, the time required for heating can be shortened. It is preferable to supply steam separately.

  The heat treatment system for asbestos-containing waste will be described in detail with reference to FIG. Most of asbestos-containing wastes such as asbestos-containing building materials that are peeled off at the time of building demolition are collected as plate-like waste. The plate-like asbestos-containing waste is transported from the dismantling site to a storage provided in the vicinity of the heat treatment system without being crushed and stored until heat treatment is performed.

  The heat treatment system includes a container 10 that contains a plurality of wastes 1 containing asbestos, a superheated steam generator 20 that generates superheated steam, a container 10, receives superheated steam from the superheated steam generator 20, and is overheated. And a heater 30 for heating the plurality of asbestos-containing wastes 1 under a steam atmosphere.

  The plurality of asbestos-containing wastes 1 are plate-shaped, and are stored in the container 10 while being separated from each other. The plurality of asbestos-containing wastes 1 can be stacked in the vertical direction so that one surface faces the bottom surface of the container 10 or can be disposed in the horizontal direction. Moreover, it can also arrange | position so that it may incline with respect to the ground. In FIG. 1, it is shown that they are stacked in the vertical direction.

  Thus, when arrange | positioning it piled up in the perpendicular direction, in order to space apart the asbestos-containing waste 1 from each other, as shown in FIG. 2 (a), after placing one asbestos-containing waste 1a, the asbestos-containing waste A plurality of spacers 2 can be disposed on the waste 1a, and another asbestos-containing waste 1b can be disposed thereon. The spacer 2 may have any shape as long as it can form an interval in which the superheated steam can flow between the asbestos-containing waste 1a and the asbestos-containing waste 1b.

  As an example of the spacer 2, if the asbestos-containing waste 1 has a thickness of about 6.5 mm, it has a shape such as a cube or a rectangular parallelepiped having a thickness that can be separated by about 6.5 mm, or a spherical shape. can do. The material of the spacer 2 may be any material as long as it can withstand the heating temperature of about 800 ° C. to 1100 ° C., and examples thereof include metals such as iron, glass, and ceramic. Glass or ceramic is preferable because it can be used as a cement material. In addition, any material may be used as long as it is a material that volatilizes at about 800 ° C. to 1100 ° C. However, by using this material, only the detoxified waste is obtained after the heat treatment, and the subsequent reuse, etc. In this case, the operation of collecting the spacer 2 is unnecessary, which is advantageous in terms of work efficiency and work cost.

  In addition, as the spacer 2, it is possible to adopt a piece that has become a small piece at the stage of peeling the asbestos-containing building material. This small piece is also an asbestos-containing waste and can be rendered harmless by heat treatment in the same manner as the plate-shaped one.

  By repeating the operation of disposing the asbestos-containing waste 1 and disposing the spacer 2 thereon, a plurality of asbestos-containing wastes 1 as shown in FIG. In addition, a set of wastes composed of a plurality of asbestos-containing wastes sandwiched between the spacers 2 are connected with an elongated metal plate, etc., and fixed so as not to be separated, so that they are arranged at an inclination or horizontally. It can also be arranged in an array.

  The container 10 is open at the top and has a plurality of holes 11 on the side and bottom. The container 10 is made of a material that can withstand a heating temperature of about 800 ° C. to 1100 ° C. For example, it can be manufactured using ceramic, brick, stainless steel, titanium, nickel alloy or the like. You may produce using an expanded metal etc.

  Here, the container 10 is illustrated in FIG. A container 10 shown in FIG. 3 is provided with a plurality of slit-like holes 11 on the side surface and the bottom surface, and superheated steam can flow through the holes 11. Note that the superheated steam that has flowed into the container 10 through the hole 11 enters a gap formed between the two asbestos-containing wastes 1 and simultaneously heats both sides of the asbestos-containing wastes 1. The container 10 can be stacked with a plurality of containers having the same size and shape. In this way, by putting a stack of a plurality of containers 10 into the heater 30, more heat treatment of asbestos-containing waste can be performed at the same time.

  As another embodiment of the container 10, as shown in FIG. 4, the container 10 is configured to include a support portion 12 made of a plurality of plates extending in the vertical direction from the bottom surface, on which the asbestos-containing waste 1 can be placed. You can also. In this case, the spacer 2 becomes unnecessary, and the asbestos-containing wastes 1 can be separated by the support portion 12.

  The container 10 can have wheels at the bottom. Thereby, it can be moved easily. Moreover, conveying apparatuses, such as a conveyor, can be installed in the heater 30, and can also be arrange | positioned on it. In this case, the container 10 may only be placed on the transfer device or may be fixed.

  In the case of being fixed to the transport device, a configuration as shown in FIG. 5 can be adopted. That is, the container 10 includes a bottom plate 13, a side plate 14 that is inclined with respect to the vertical direction, and a protruding portion 15 that protrudes from the bottom plate 13, and is fixed to a conveyor 40 that is a transfer device. In the configuration shown in FIG. 5, a plurality of containers 10 are fixed to the conveyor 40, and a plurality of asbestos-containing wastes 1 are continuously introduced from the direction indicated by the arrow A, and indicated by the arrow B The present invention can be applied to a case where wastes that are heat-treated continuously in the direction are discharged. In this configuration, since the side plate 14 is inclined and includes the protruding portion 15, the asbestos-containing waste 1 can be stood and arranged.

  In the configuration shown in FIG. 5, the conveyor 40 is operating while a plurality of asbestos-containing wastes 1 are contained in one container, and the asbestos-containing waste 1 is continuously charged into the containers 10. Then, heat treatment is performed. The inside of the heater 30 is an overheated steam atmosphere, and is heated for a predetermined time by the conveyor 40 whose moving speed is adjusted. After heating for a predetermined time, it has reached a position for discharging the waste, and the container 10 is fixed to the conveyor 40. Therefore, only the heat-treated waste in the container 10 is discharged through the discharge port. .

  As shown in FIG. 6, the superheated steam generator 20 includes a water storage tank 21 for storing water, a boiler 22 for evaporating water, a water supply pump 23 for supplying water from the water storage tank 21 to the boiler 22, and superheated steam. And a steam superheater 24 to be generated.

  The steam superheater 24 may combust fuel and be superheated by a high-temperature combustion gas, but may be based on electromagnetic induction overheating. Here, electromagnetic induction overheating generates a strong magnetic field by passing a strong current through the coil, and puts a metal such as iron or stainless steel that easily conducts electricity on it to generate an eddy current by electromagnetic induction. This is a heating method utilizing the principle that metal generates heat by resistance. When steam is heated by electromagnetic induction overheating, it can be used as an electromagnetic induction overheating apparatus in which a cylindrical tube made of iron or stainless steel or the like and a conductive wire wound around the outer periphery thereof.

  The superheated steam generated by the superheated steam generation apparatus 20 is steam at a temperature exceeding about 100 ° C. at almost atmospheric pressure. However, when it is supplied to the heater 30 at a temperature such as 300 ° C. or 400 ° C. lower than 800 ° C., the temperature in the heater 30 once heated to about 800 ° C. to 1100 ° C. is lowered, and again reaches that temperature. It takes time to heat. In addition, energy for heating to that temperature is consumed. Therefore, in order not to lower the temperature in the heater 30 once heated, it is preferable to heat and supply at about 800 ° C. to 1100 ° C.

  Referring again to FIG. 1, the heater 30 includes heating means 31 that heats a plurality of waste containing asbestos contained in the container 10, receives superheated steam from the superheated steam generation device 20, and has a superheated steam atmosphere. Below, by heating a plurality of asbestos-containing wastes by the heating means 31, the crystallization water in the asbestos is dehydrated to render the asbestos harmless. Therefore, the heater 30 is hollow to accommodate the container 10 and has a high hermeticity so that the received superheated steam does not leak, and the heater 30 can also be heated and held for about 10 to 120 minutes. High structure. The wall of the heater 30 can be made of ceramic, brick, stainless steel, titanium, nickel alloy or the like. The heat insulation property can be enhanced by attaching the heat insulating material so as to surround them.

  The heating means 31 may be an electric heater or a heating furnace that can be heated to a temperature of about 800 ° C. to 1100 ° C. The electric heater can be attached to any one, two, or all of the floor, ceiling, and side walls of the heater 30. In addition, when the wall of the heater 30 is made of stainless steel having high thermal conductivity, the electric heater can be attached so as to be wound around the outer periphery thereof. When a heating furnace is installed, a heater 30 is installed in the heating furnace and heated by a combustion gas from the outside of the heater 30, or a pipe is provided inside the heater 30 and generated in the pipe by the heating furnace. It can be heated by passing hot combustion gas.

  The heater 30 has a steam receiving nozzle 32 for receiving the superheated steam generated by the superheated steam generation device 20. The superheated steam supplied through the steam receiving nozzle 32 diffuses in the heater 30 and enters the gaps between the asbestos-containing wastes 1 to give heat to both sides of the asbestos-containing wastes 1. The inside of the heater 30 is heated to about 800 ° C. to 1100 ° C. by the superheated steam and the heating means 31 and is maintained at that temperature for about 10 minutes to 120 minutes. This is because the heater 30 includes a thermometer and a temperature controller, whereby the internal temperature can be controlled to that temperature.

During heating and temperature holding in the heater 30, in the asbestos-containing waste 1, the temperature is transferred from the outer surface in contact with the superheated steam to the inside, and the inside gradually approaches about 800 ° C. to 1100 ° C. Along with this, the reaction shown in the above chemical formula 1 also takes place inside, and the water of crystallization is dehydrated from asbestos and converted into harmless forsterite to be rendered harmless. In the present invention, when heated in a superheated steam atmosphere, it is further decomposed into a solid material mainly composed of 2CaO.SiO ₂ and CaO.

  In FIG. 1, in order to heat-treat more asbestos-containing waste 1, a plurality of containers 10 are stacked and accommodated in a heater 30, and heating means 31 are attached to the ceiling and both side walls. The lowermost container 10 is disposed on two rails 33, and nine containers are stacked on the container 10. In each container 10, plate-shaped asbestos-containing wastes 1 having different sizes are stacked via spacers 2.

  FIG. 7 is a diagram showing a second embodiment of the heat treatment system. In the heat treatment system shown in FIG. 7, a conveyor 40 shown in FIG. 5 and a plurality of containers 10 are fixed to the conveyor 40 in the heater 30, and an inlet and an outlet for receiving the asbestos-containing waste 1 are provided. I have. In addition, a waste charging device 50 for charging a plurality of asbestos-containing wastes 1 into the container 10 through the receiving port, a cooling device 60 for cooling the waste discharged from the heater 30, and cooling. And a pulverizing device 70 for pulverizing the waste.

  The waste input device 50 carries a plurality of asbestos-containing wastes 1 and a bowl 51 for carrying asbestos, and the bowl 51 is turned upside down. It includes a bag transporter 53 that feeds the object 1 through the chute 52 to the receiving port and throws it into the container 10. Only the upper part of the tub 51 is opened, and the asbestos-containing waste 1 is, for example, a size into which ten sheets can be put. As the kite transporting device 53, an unloader, a slider, or the like can be used to transport the kite 51 upward.

  The asbestos-containing waste 1 is put into the container 10 along the side plate 14 inclined with respect to the vertical direction, and slides on the bottom plate 13 by the inclined side plate 14, but the end portion comes into contact with the protruding portion 15 and stops. And accommodated in the container 10. The protrusions 15 are provided at predetermined intervals and separate the asbestos-containing waste 1 from each other. Since a plurality of containers 10 are fixed to the conveyor 40 and the conveyor 40 is operating, when a set of a plurality of asbestos-containing wastes 1 placed in one basket 51 is accommodated in one container 10 The container 10 moves, the next container is located under the receiving port, and the next set of asbestos-containing wastes are charged.

  The conveyor 40 heats the container 10 to a heating temperature of about 800 ° C. to 1100 ° C., and then moves the container 10 at a speed so as to be held at that temperature for about 10 minutes to 120 minutes. Thereby, heat processing can be performed continuously.

  The system shown in FIG. 7 includes a cooling device 60 for cooling waste that has been detoxified and discharged, and the cooling device 60 supplies a water storage tank 61 that stores cooling water and cooling water. The cooling water pump 62, a cooling tank 63 that accommodates waste, and an injection nozzle 64 that is attached to the cooling tank 63 and injects cooling water toward the waste.

  The waste discharged from the heater 30 has a temperature of about 800 ° C. to 1100 ° C. When cooling water is injected from the injection nozzle 64 to this, the cooling water receives sensible heat and latent heat of vaporization from the waste and is vaporized. Furthermore, it receives sensible heat and becomes superheated steam. The waste is cooled by applying sensible heat and latent heat of evaporation to the cooling water. Note that when the waste after cooling is in a moist state, it becomes difficult to reuse it as cement or the like, so cooling water is supplied to the extent that the waste does not get wet, thereby cooling the waste.

The waste cooled by the cooling water is sent to the pulverizer 70. In FIG. 7, it is sent from the cooler 60 to the lower crusher 70 by its own weight. In addition, a valve is provided between the cooling device 60 and the pulverizing device 70, and after cooling with the cooling device 60, the valve is opened so that waste can be put into the pulverizing device 70. The crusher 70 can be a roll crusher, a tube crusher, or the like. Since the waste is already detoxified and mainly composed of 2CaO.SiO ₂ and CaO, it can be reused as cement. After pulverization by the pulverizer 70, the pulverizer 70 is carried to a truck by a conveyor or the like, and then baked in a kiln or the like to be cemented for reuse.

  In the embodiment shown in FIG. 7, the waste is cooled by cooling water, and the generated superheated steam is not used. For this reason, thermal efficiency is low. Therefore, in order to effectively use superheated steam, improve thermal efficiency, reduce energy consumption, and reduce operating costs, a system can be constructed as follows.

  FIG. 8 is a diagram showing a third embodiment of the heat treatment system. In the embodiment shown in FIG. 8, a plurality of preheaters 80 and 81 having different heating temperatures and a plurality of coolers 90 and 91 having different cooling temperatures are provided. One heating furnace 82 is provided. These are separated by seven gates 100 to 106, and by lowering the gates 100 to 106, the container 10 can be moved to an adjacent preheater, heating furnace or heater or cooler. Has been. For example, the container 10 includes wheels and is movable on a floor or a rail. The gates 100 to 106 are opened by being lowered to the basement and closed by being raised again.

  In the embodiment shown in FIG. 8, first, the gate 100 is opened, and the container 10 is placed in the preheater 80. The preheater 80 is supplied with the superheated steam generated by the cooler 91, and preheats the plurality of asbestos-containing wastes 1 accommodated in the container 10 by the superheated steam. In the cooler 91, superheated steam at about 250 ° C. to 450 ° C. is generated, so that the preheater 80 is preheated to about 150 ° C. to 300 ° C. When preheated to this temperature, the gate 101 separating the preheater 80 and the preheater 81 is opened, the container 10 is moved to the preheater 81, and the gate 101 is closed.

  The preheater 81 is supplied with the superheated steam generated by the cooler 90, and preheats the plurality of asbestos-containing wastes 1 accommodated in the container 10 by the superheated steam. The cooler 90 generates superheated steam at about 500 ° C. to 700 ° C., and the preheater 81 is preheated to about 300 ° C. to 500 ° C. When preheated to this temperature, the gate 102 that partitions the preheater 81 and the preheater 82 is opened, the container 10 is moved to the heating furnace 82, and the gate 102 is closed.

  The heating furnace 82 heats the plurality of asbestos-containing wastes 1 accommodated in the container 10 to about 800 ° C. to 1100 ° C. by an electric heater or combustion gas. When heated to this temperature, the gate 103 that partitions the heating furnace 82 and the heater 30 is opened, the container 10 is moved to the heater 30, and the gate 103 is closed.

The heater 30 receives superheated steam from the superheated steam generator 20 in advance, and heats the inside to about 800 ° C. to 1100 ° C. by the heating means 31. The asbestos-containing waste 1 sent from the heating furnace 82 has reached a temperature necessary for the heat treatment, and the heater 30 waits for about 10 to 120 minutes after the container 10 is put, When there is a temperature drop, it is heated by that drop. By the heating by the heating furnace 82 and the heater 30, the crystal water in the asbestos is dehydrated, chrysotile is converted into forsterite, and further decomposed to become a solid mainly composed of 2CaO · SiO ₂ and CaO.

  After about 10 to 120 minutes have elapsed, the gate 104 is opened, moved to the cooler 90, and the gate 104 is closed. The detoxified waste is cooled by being sprayed with water and giving sensible heat and latent heat of evaporation to the water. Here, the waste is cooled to about 650 ° C. to 900 ° C. and produces superheated steam of about 500 ° C. to 700 ° C. When cooled to this temperature, the gate 105 separating the cooler 90 and the cooler 91 is opened, the container 10 is moved to the cooler 91, and the gate 105 is closed.

  The waste cooled by the cooler 90 is again sprayed with water and cooled by giving sensible heat and latent heat of vaporization to the water. Here, the waste is cooled to about 400 ° C. to 600 ° C. and produces superheated steam of about 250 ° C. to 450 ° C. When cooled to this temperature, the gate 106 that partitions the cooler 91 is opened, taken out from the cooler 91, the gate 106 is closed, and then naturally cooled.

  In addition, although the temperature of the waste and the temperature of the superheated steam were illustrated in the above, this is merely an example, and the temperature can be higher or lower depending on the amount of water supply.

  FIG. 9 is a diagram showing a fourth embodiment of the heat treatment system. The embodiment shown in FIG. 9 is configured to further include a reaction device 110 in addition to the configuration shown in FIG. The asbestos-containing waste 1 contains an organic compound such as a volatile organic compound (VOC) as a paint or an adhesive. This VOC includes benzene, toluene, xylene, formaldehyde, paradichlorobenzene, ethylbenzene and the like. These organic compounds are one of the causes of health damage caused by photochemical oxidants, are air pollutants, and cannot be directly released into the atmosphere.

Therefore, this organic compound is decomposed into carbon dioxide gas, water, or the like by the reactor 110 and then released into the atmosphere. In addition to the reactor 110, a cooling device for cooling the decomposition gas, a filter for removing suspended solids asbestos unreacted materials and the like contained in the decomposed gas, a cleaning device for collecting the chlorine and SO _x in the decomposed gas It can also be provided.

  In addition to the volatile organic compound generated in the heater 30, the reactor 110 is supplied with superheated steam, and is also supplied with air as necessary. In the reactor 110, these are heated to a predetermined temperature, the volatile organic compound is reacted with superheated steam, and decomposed into hydrogen, carbon monoxide, etc. by hydrolysis and thermal decomposition. Moreover, it oxidizes by supplying air, and produces | generates a carbon dioxide and water. The reactor 110 is heated to a temperature of about 900 ° C to 1200 ° C. Examples of the reaction apparatus 110 include an apparatus provided with an electric heater in a cylindrical tube, an electromagnetic induction heating apparatus in which a conducting wire is wound around the outer periphery of the cylindrical tube, and the like.

  When the cooling device, the filter, and the cleaning device are provided, the cooling device rapidly cools the cracked gas having a low molecular weight. Since the asbestos unreacted substance is contained in the cracked gas as a suspended matter, the suspended matter is collected by a filter and the suspended matter is removed from the decomposed gas. A filter can be comprised from the pre filter which consists of a coarse nonwoven fabric and a HEPA filter used as a fine main filter.

The scrubber can be a scrubber, and contains an alkaline aqueous solution in a container. The decomposition gas is allowed to react with the alkali by passing through the aqueous solution, so that halogen such as chlorine in hydrogen chloride, carbon dioxide Partly collects and removes SO _{x and the} like. As the alkali, potassium hydroxide, sodium hydroxide, or calcium hydroxide can be used. In the cleaning device, carbon dioxide that has not reacted with the alkali and air that has not been used in the reaction in the reaction device 110 are moved into bubbles in the alkaline aqueous solution and moved to the upper portion of the container of the cleaning device, and are sucked by the blower into the atmosphere. Dissipated in.

Asbestos-containing waste 1 includes chrysotile (Mg ₃ Si ₂ O ₅ (OH) ₄ ), which is a main component of asbestos, and silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), which are components of cement, Ferric oxide (Fe ₂ O ₃ ), calcium oxide (CaO) and the like are included. When waste containing about 25% of the total weight of chrysotile is heated in a superheated steam atmosphere at a temperature of 800 ° C. or higher, the chrysotile disappears and forsterite is generated. In the heat treatment using this superheated steam, Forstrite also disappears, and the components after the heat treatment are mainly 2CaO.SiO ₂ (belite) and CaO (quick lime). This is CaO which is a calcareous material and SiO ₂ which is a clay material, which are the main components of cement.

For this reason, the waste heat-treated in the superheated steam atmosphere is cooled and then pulverized as it is by a pulverizer 70 such as a roll crusher or tube crusher without adding any additives or removing unnecessary components. Then, the clinker can be formed by firing with a kiln or the like. Clinker is a sinter mass which is obtained by high temperature firing cement raw materials in kilns, belite, aluminate phase _{(3CaO · Al 2 O 3)} , ferrite phase _{(4CaO · Al 2 O 3 ·} Fe 2 O 3 ) And alite (3CaO · SiO ₂ ), and the strength of the cement is expressed by these hydraulic compounds. The belite, aluminate phase, ferrite phase, and alite are produced by pulverizing and firing CaO, SiO ₂ , Al ₂ O ₃ , and Fe ₂ O ₃ that are cement raw materials. Cement can be made by adding about 3% to about 5% gypsum to the clinker. The reason why gypsum is added here is to suppress the reaction between the aluminate phase and water.

  So far, the heat treatment system of the present invention has been described in detail with reference to the embodiments shown in the drawings, but the present invention is not limited to the above-described embodiments, and other embodiments, additions, Modifications, deletions, and the like can be made within the scope that can be conceived by those skilled in the art, and any aspect is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

The figure which showed 1st Embodiment of the heat processing system. The figure which showed the place which piled up the some asbestos containing waste on both sides of the spacer. The figure which illustrated the container. The figure which showed another embodiment of the container. The figure which showed the structure by which the conveyor is installed in a heater and several containers are being fixed to the conveyor. The figure which illustrated the composition of the superheated steam generating device. The figure which showed 2nd Embodiment of the heat processing system. The figure which showed 3rd Embodiment of the heat processing system. The figure which showed 4th Embodiment of the heat processing system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Waste containing asbestos, 2 ... Spacer, 10 ... Container, 11 ... Hole, 12 ... Supporting part, 13 ... Bottom plate, 14 ... Side plate, 15 ... Projection part, 20 ... Superheated steam generator, 21 ... Water storage tank, 22 ... Boiler, 23 ... Feed water pump, 24 ... Steam superheater, 30 ... Heater, 31 ... Heating means, 32 ... Steam receiving nozzle, 33 ... Rail, 40 ... Conveyor, 50 ... Waste input device, 51籠, 52 ... Chute, 53 ... 籠 conveying device, 60 ... Cooling device, 61 ... Water storage tank, 62 ... Cooling water pump, 63 ... Cooling tank, 64 ... Injection nozzle, 70 ... Crushing device, 80, 81 ... Preheater , 82 ... heating furnace, 90, 91 ... cooler, 100 to 106 ... gate, 110 ... reactor

Claims (8)

A heat treatment system for heating and detoxifying waste containing asbestos,
Containing a plurality of the asbestos-containing wastes spaced apart from each other, and having a plurality of holes on the side surface and the bottom surface;
A superheated steam generator for generating superheated steam;
Heating means for heating the plurality of asbestos-containing wastes, containing the container, receiving the superheated steam from the superheated steam generator, and under the superheated steam atmosphere, the plurality of asbestos-containing wastes by the heating means A heater that dehydrates the water of crystallization in asbestos and detoxifies the asbestos by heating the object ,
The plurality of heated asbestos are cooled by spraying water toward the heated plurality of asbestos-containing wastes, installed in the subsequent stage of the heater, containing the container, and heating the plurality of asbestos-containing wastes. A cooler that discharges superheated steam generated by waste containing asbestos;
A preheater installed in the front stage of the heater, containing the container, and preheating the plurality of asbestos-containing waste housed in the container by the superheated steam discharged from the cooler. Processing system.   The said container is a heat processing system of Claim 1 which accommodates these some asbestos containing waste materials which the spacer was inserted | pinched between each and the mutually separated.   The heat treatment system according to claim 1 or 2, wherein the heater accommodates a plurality of the containers and heat-treats the plurality of asbestos-containing wastes accommodated in the plurality of containers at a time.   The heat treatment system according to claim 1, wherein the heating unit is an electric heater attached inside or outside the heater.   The heating according to any one of claims 1 to 4, wherein the heater heats the plurality of asbestos-containing wastes at a temperature of 800 ° C to 1100 ° C for 10 minutes to 120 minutes under the superheated steam atmosphere. Processing system. The said heat processing system is a heat processing system of any one of Claims 1-5 containing several said preheater from which heating temperature differs, and several said cooler from which cooling temperature differs. The heater includes an inlet for receiving the asbestos-containing waste, and an outlet for discharging the heat-treated waste,
A conveying device installed in the heater and conveying the container from the receiving port to the discharging port;
It comprises a tub in which the plurality of asbestos-containing wastes can be put, transports the plurality of asbestos-containing wastes by moving the tub, and puts it into the container disposed on the transfer device through the receiving port The heat processing system of any one of Claims 1-6 further including the waste charging device to perform. The reactor according to any one of claims 1 to 7 , further comprising a reactor for reacting the superheated steam discharged from the heater with a volatile organic compound generated from the asbestos-containing waste to decompose the volatile organic compound. The heat treatment system according to item 1.

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